Increasingly, the field of photonics is helping to achieve high bandwidth communications to replace traditional electrical connections. Fiber optic communication involves the process of transporting data at high speeds by using light to transmit a signal over a glass fiber. However, as communication speeds increase, traditional single mode laser configurations have become impractical and instead, most solutions achieve high transmission rates via multiplexing.
A traditional laser generates infrared light which may then be tuned and filtered to a specific wavelength. Once this single wavelength is established, data is placed on the transmission signal and transmitted via a glass fiber. However, the amount of data that can be transmitted via a single wavelength/single mode fiber is limited. Although enormous bandwidth may be available on a single-mode optical fiber, transmission of data sufficient to occupy that bandwidth would result in a data rate far higher than what can be handled by both senders and receivers. Therefore, in an attempt to deal with this barrier and satisfy the need for transmission of high volumes of data, multiple optical laser channels are usually combined. Typically, 4-10 channels are combined to achieve a higher data rate, and although each individual channel may have a lower data rate than a single mode laser, the aggregate of the multiple data streams is well in excess of that which can be technologically achieved by a single mode signal.
In order to aggregate multiple individual laser signals, individual signals are created as in a single mode application and the multiple lasers are positioned parallel to each other. These individual light streams of varying wavelengths are then focused and passed through a multiplexer to combine the multiple wavelengths onto a single strand of fiber.
Finally, the receiving end of the signal reverses the process. A de-multiplexer separates the data stream received from the optical fiber and separates the signal into its component wavelengths. These individual data streams are then routed to photodetectors to convert the light into electrical signals which can then be used with traditional electronic components. Logic circuits on the host device are then able to process the signal just as if it had been received as a traditional electrical signal over a copper wire.